N-甲基-D-天冬氨酸受体与脑卒中的关系及其核素显像剂

Relationship between N-methyl-D-aspartate receptor and stroke as well as its nuclide imaging agents

  • 摘要: 脑卒中具有极高的致死率和致残率,在当今老龄化社会中其危害性日益突出。N-甲基-D-天冬氨酸受体(NMDAR)是一类配体门控离子型谷氨酸受体,参与兴奋性突触传递、突触可塑性和神经精神疾病的发生和发展。NMDAR在不同的脑区分布有差异,如海马和皮层密度最高,这些区域对脑缺血很敏感。谷氨酸介导的兴奋性神经毒对脑卒中的发生、发展起着极其关键的作用,引起了人们对中枢神经系统兴奋性神经递质和NMDAR的高度重视。同时,脑卒中后对Ca2+通透的NMDAR、α-氨基-3-羟基-5-甲基-4-异恶唑丙酸受体、海人藻酸受体高度兴奋,引起细胞内钙超载,进而触发级联细胞死亡。NMDAR有特殊的结构和药理学特性,对NMDAR显像剂的研究为脑卒中的早期诊断和研发特异性拮抗剂提供了新的靶点。通过活体断层显像可以观察到缺血缺氧后神经细胞的变化,从而对NMDAR拮抗剂的神经保护作用作出评价。

     

    Abstract: Stroke is one of the leading causes of death and disability, especially for the old population in modern world.As one of ligand-gating ionotropic glutamate receptors, N-methyl-D-aspartate rece pto r(NMDAR)involves in excitatory synaptic transmission, synaptic plasticity and the cause and development of numerous neurological as well as psychiatric disorders.Since the distribution of NMDAR varies in different regions, certain brain regions such as hippocampus and cortex with the highest density of NMDAR, are especially sensitive to ischemia.Much emphasizes have been put on the changes of excitatory neurotransmission and NMDAR in central nervous system after ischemia, because the glutamate-mediated excitatory neurotoxicity play a key role in the development of stroke.It has been shown that neuronal death after ischemia results from excessive Ca2+ influx, which is due to the hyperactivity of NMDAR, Ca2+ permeable α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor, kainic acid receptors and/or other ion channels permeable to Ca2+.The increase of intracellular Ca2+ triggers the cascades of cell death.With specific structure and pharmacology properties, this study of the tracer of NMDAR give the target for early diagnosis and developing of specific antagonist.Elucidating the changes in interneurons after ischemia/ hypoxia with tomography in vivo will help to understand the mechanisms underlying the neoroprotection of antagonist.

     

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